The research of the last five years is summarized. It comprises: 1. Investigations of protein dynamics. 2. The effect of pressure upon model systems, monomeric and oligomeric proteins, lipid phase transitions and enzyme activity. 3. Resolution of multicomponent fluorescent systems by phase and modulation measurements. 4. Theory of asymmetric ligand binding and its implications for hemoglobin. 5. Application of the Langevin distribution to polar fluorophore-solvent interactions. 6. Synthesis and usage of new environmentally sensitive fluorescent probes. A plan of research for the coming five year period is presented: Investigations on protein dynamics will be directed to the detection of the ultrafast protein tyrosine motions predicted by molecular dynamics and to the influence of dynamics in the chemical potential of proteins. High-pressure studies will be continued centering on the dissociation of oligomeric proteins. A new subject of study will be the influence of pressure upon proton dissociation of fluorophores in lipid vesicles, in both ground and excited state. Environmentally sensitive fluorescent probes will be employed to study the stability of proteins to temperature and pressure at high dilution. The synthesis of probes of this type suitable to elicit monoclonal antibodies will be attempted. One completely new research development is proposed: The application of differential methods current in the fluorescence spectroscopy of solutions to the study of cells by fluorescence microscopy..